
<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title>金字塔</title>d
		<style type="text/css">
			hr{
			width: 'i' px;
				
			}
		</style>
		
		<script type="text/javascript">
		
			document.write("<h1 style='text-align: center;'>打印倒正金字塔直线</h1>");
			for(var i=400;i>0;i-=50){
			var ss= i+'px';
		document.write("<div style=' width: "+ss+";align=center;' /><hr/><br /></div>");
			}
//			document.write("<div style='margin: auto;width :10px;border-bottom:1px solid black ;'><br /></div>");
			for(var i=100;i<=400;i+=50){
			var ss= i+'px';
	
		
		document.write("<div style=' width: "+ss+";align=center;' /><hr/><br /></div>");
		
			}
		</script> 
	</head>
	<body>
	</body>
</html>
